PIGMENTED INKS FORMED USING MICROFILTRATION

The invention relates to a pigment-based ink composition for inkjet printing the ink composition pigment particles, wherein said ink composition has a filterability of at least 80% wherein filterability is determined by the following test; a sample of said pigment-based ink is divided into four 100 ml aliquots and a first aliquot is filtered through a chemically inert membrane having a porosity of 1.0 mum and a diameter of 47 mm and using a vacuum of 20 inches of Hg and measuring the time it takes to complete the filtration, T1, a second and third aliquot are sequentially passed through the same filter under the same filtering conditions, the fourth aliquot is then passed through the same filter under the same conditions while measuring the time it takes to complete the filtration of the fourth aliquot, T4, the time of T1 is divided by T4 and multiplied by 100 to obtain the filterability.